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Standard Quality Control Testing, Virus Penetration, and Glove Durability
Published in Robert N. Phalen, Howard I. Maibach, Protective Gloves for Occupational Use, 2023
Scanning electron microscopy (SEM) provided evidence for the actual nature of the porous structure. Custom mounting of the glove material in both its original and extended state allowed these observations: Upon extension, the nature of the connecting fibrillar structure becomes visible. In nonfatigued glove material, the fibrils are intact, whereas in the fatigued glove material, fibrillar breakage, etc., was observed.71 Thus, the rapid onset of glove rupture can be explained by a classic fatigue mechanism where the glove material behaves normally until the accumulation of fatigue cycles (and stress) leads to a porous structure, crazing, formation of cracks and holes, and finally catastrophic rupture. In the extended state, the pores may exceed the diameter of viruses of concern. However, the flow needed for virus transport through the barrier (see Section 11.3) would be quite different from flow through a “hole.”
Aircraft Decontamination and Mitigation
Published in Brian J. Lukey, James A. Romano, Salem Harry, Chemical Warfare Agents, 2019
William T. Greer Jr., Angela M.G. Theys, William R. Davis, Kenneth J. Heater
The main concern with peroxide decontamination is the adverse effects on aircraft materials, which have been demonstrated for several mVHP conditions as well as mHPV conditions (Heater et al., 2004, 2006, 2008, 2009, 2010). These tests focused on common aircraft materials, including a variety of metals, plastics, coatings, elastomers, lubricants, textiles, wiring, and electronic equipment. The Steris VHP system has been studied far more extensively than the Bioquell HPV system, but in the testing conducted, both VHP and HPV adversely affected the adhesion of painted coatings and caused softening and blistering of polysulfide and polythioether sealants. VHP also caused crazing of transparency materials, polycarbonate and cast acrylic; blistering of liquid crystal displays (LCDs); and failure of dry film lubricants. Lower concentrations of peroxide cause fewer problems, but the effects become more severe with repeated exposures.
Scintillation Of Organic Materials
Published in Sam Beddar, Luc Beaulieu, Scintillation Dosimetry, 2018
Marie-Ève Delage, Luc Beaulieu
Light emission of organic scintillators depends on the factors related to the nature of the scintillator. As a consequence, different spectral bands and response times can be encountered when looking through the properties of organic scintillating materials. Each of these materials will have its proper fluorescence intensity exponential decay over time. The response of organic molecules to excitation also depends on the nature of the scintillator, the type of ionizing particles (directly or indirectly ionizing), and the energy of the incident particles, allowing the possibility of using these dependencies to our advantage in applications such as pulse shape discrimination. The light response is also dependent on the degree of damage inflicted to the scintillator. This damage can be caused by a prolonged exposure to ionizing radiation; an exposure to light and oxygen, which for plastics leads to polymer degradation; or surface crazing that compromises the internal total reflection, a phenomenon on which relies the transmission of the scintillation light. Key concepts related to these dependences of the efficiency of the organic scintillators light emission will be presented in addition to a description of the selected organic materials (Section 1.3.6).
Covid-19-Associated Retinopathy: A Case Report
Published in Ocular Immunology and Inflammation, 2020
Pierre Gascon, Antoine Briantais, Emmanuelle Bertrand, Prithvi Ramtohul, Alban Comet, Marie Beylerian, Lauren Sauvan, Laure Swiader, Jean Marc Durand, Danièle Denis
Supra-aortic vascular screening – including ophthalmic arteries, with doppler and computed tomography (CT)-scan was normal. Chest CT-scan revealed bilateral ground-glass opacities with crazing paving pattern and some bronchus distortion consistent with SARS-Cov-2 associated pneumonia (Figure 1b). Reverse transcriptase-polymerase chain reaction (RT-PCR) on nasopharyngeal swab confirmed the presence of the virus in the airways. RT-PCR on conjunctival sample performed simultaneously because of ophthalmologic manifestations was negative. PCRs were negative for other coronaviruses (HCoV-E229, HCoV-NL63, HCoV-KU1, HCoV-OC43) and other respiratory viruses (A and B influenza, rhinovirus, respiratory syncytial virus, parechovirus, adenovirus, enterovirus, metapneumovirus, bocavirus, parainfluenzae). Serological tests did not show evidence of an acute infection (A, B, C and E hepatitis, human immunodeficiency virus, Epstein-Barr virus, EBV, cytomegalovirus, herpes simplex virus, Treponema pallidum, Chlamydia pneumoniae, Mycoplasma pneumoniae, Legionella pneumophila, Coxiella burnettii). As the patient recently came from Comoros, enzyme-linked sorbent immunoassays for dengue and chikungunya were performed and were also negative. Due to the lack of validated consensus, no treatment was prescribed.
A comparative evaluation of resin- and varnish-based surface protective agents on glass ionomer cement – a spectrophotometric analysis
Published in Biomaterial Investigations in Dentistry, 2020
Shreya Tyagi, Abi M. Thomas, Neeta Devi Sinnappah-Kang
The setting time of GIC is seven minutes from the start of the mix. The moisture isolation is crucial during this period [7]. According to Gemalmaz et al., the amount of soluble matrix is maximum during the early phases of GIC formation and the most sensitive period is the first six minutes after mixing. Any moisture contamination during this phase can cause the loss of soluble matrix and reduce its physical properties [8]. Hence the GIC should be protected from additional water contamination during the initial stages to prevent dissolution of ions whereas once it sets; it should be protected against dehydration to avoid cracking and crazing [9].